The present invention relates in general to a device for adjusting the vertical and inclined positions of a vehicle seat, and in particular, to a position adjuster including at each lateral side of the seat a five-bar linkage assembled of an underframe, a seat carrier bar, a pair of two-arm support levers hinged to the underframe, a coupling bar hinged between the outer arm of one of the support levers and an end portion of the carrier bar, and the other end portion of the carrier bar being hinged to the outer arm of the other support lever. The inner arms of the support levers are provided with gear segments cooperating, respectively, with arresting teeth controlled by a hand lever which is hinged to the underframe.
From the German publication 22 06 884 a device for adjusting the vertical and angular positions of a vehicle seat in which the gear segment of the support lever is directly hinged to the seat carrying bar and cooperates with a radially displaceable sliding member. The sliding member is provided with external arresting teeth engageable with the gear segment of the assigned support lever whereas the other support lever is linked to the coupling bar and cooperates with an opposite arresting gear arranged on a swivel arm. Both arresting teeth are actuated by means of cams which are linked to driving rods connected one to another by means of a tension spring. The free ends of the driving rods are provided with notches which are coupled to a control lever hinged to the underframe and being hand-operated by a handle.
The above-described prior art vertical and angular position adjusters for vehicle seats have the disadvantage that they are assembled of a relatively large number of individual component parts and consequently are expensive to manufacture and to assemble. Moreover, such rather complicated adjusters are prone to generate rattling noises and susceptible to malfunction of individual parts. Another disadvantage of such known device is in the fact that the path of movement of the control lever is relatively long and the locking engagement of the arresting teeth in their adjusted position is not always reliable.